A revision of the megacanthoxea-bearing tetillids (Porifera, Spirophorida), with a description of a new species

A sponge collection dredged by Dr. P. WAGENAAR HUMMELINCK in the vicinity of Barbados (West Indies) contained a Cinachyralike specimen bearing large and conspicuous acanthoxea. This find induced the present author to re-examine all specimens with similar spiculation reported so far. A review of the literature revealed that a total of three such specimens has been described in two different genera, all as separate species, viz. Acanthotetilla hemisphaerica Burton, 1959, Acanthocinachyra enigmatica Levi, 1964, and Acanthocinachyra seychellensis Thomas, 1973. Both genera are reported to differ in the presence (genus Acanthocinachyra) or absence (genus Acanthotetilla) of sigmaspire microscleres. In view of the close similarity of the two genera it seemed wise to compare all the specimens. Miss S. M. STONE (British Museum (Natural History), London) kindly consented to the loan of the holotype of Acanthotetilla hemisphaerica; Dr. P. L. G. BENOIT (KOninklijk Museum voor Midden Afrika, Tervuren, Belgium) and Dr. C. LÉVI (Muséum National d’Histoire Naturelle, Paris) readily sent the specimens of Acanthocinachyra seychellensis and A. enigmatica, respectively. Dr. P. WAGENAAR HUMMELINCK (Zoölogisch Laboratorium, State University of Utrecht) is kindly thanked for his donation of the West Indian collection. Scanning Electron Microscope illustrations were made by Drs. S. WEINBERG, the other photographic illustrations by Mr. L. A. VAN DER LAAN (both ZMA), which aid is gratefully acknowledged.